LIDAR sensor system

ABSTRACT

A light detection and ranging (LIDAR) sensor system for a vehicle includes a transmitter, a receiver, and a scanner. The transmitter is configured to output a transmit beam. The transmitter includes a first grating coupler. The receiver includes a plurality of second grating couplers spaced apart from the first grating coupler.

BACKGROUND

Optical detection of range using lasers, often referenced by a mnemonic,LIDAR (for “light detection and ranging”), also sometimes referred to as“laser RADAR,” is used for a variety of applications, including imagingand collision avoidance. LIDAR provides finer scale range resolutionwith smaller beam sizes than conventional microwave ranging systems,such as radio-wave detection and ranging (RADAR).

SUMMARY

At least one aspect relates to a light detection and ranging (LIDAR)sensor system for a vehicle. The LIDAR sensor system includes atransmitter configured to output a transmit beam. The transmitterincludes a first grating coupler. The LIDAR sensor system includes areceiver. The receiver includes a plurality of second grating couplersspaced apart from the first grating coupler. The LIDAR sensor systemincludes a scanner configured to receive the beam from the transmitter,direct the transmit beam to an environment, receive a return beam fromreflection of the transmit beam by an object, and direct the return beamto the receiver.

At least one aspect relates to an autonomous vehicle control system. Theautonomous vehicle control system includes a LIDAR sensor system and oneor more processors. The LIDAR sensor system includes a first gratingcoupler configured to output a transmit beam and a second gratingcoupler spaced apart from the first grating coupler. The LIDAR sensorsystem includes a scanner configured to receive the transmit beam fromthe transmitter, direct the beam to an environment, receive a returnbeam from reflection of the transmit beam by an object, and direct thereturn beam to the second grating coupler. The one or more processorsare configured to determine at least one of a range to the object or avelocity of the object based on the return beam and control operation ofan autonomous vehicle responsive to the at least one of the range or thevelocity.

At least one aspect relates to an autonomous vehicle. The autonomousvehicle includes a transmitter configured to output a transmit beam. Thetransmitter includes a first grating coupler. The autonomous vehicleincludes a receiver. The receiver includes a plurality of second gratingcouplers spaced apart from the first grating coupler. The autonomousvehicle includes a scanner configured to receive the transmit beam fromthe transmitter, direct the transmit beam to an environment, receive areturn beam from reflection of the transmit beam by an object, anddirect the return beam to the receiver. The autonomous vehicle includesa steering system, a braking system, and a vehicle controller. Thevehicle controller includes one or more processors. The one or moreprocessors are configured to determine at least one of a range to theobject or a velocity of the object using the return beam and controloperation of at least one of the steering system and the braking systemresponsive to the at least one of the range or the velocity.

Those skilled in the art will appreciate that the summary isillustrative only and is not intended to be in any way limiting. Any ofthe features described herein may be used with any other features, andany subset of such features can be used in combination according tovarious embodiments. Other aspects, inventive features, and advantagesof the devices and/or processes described herein, as defined solely bythe claims, will become apparent in the detailed description set forthherein and taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations are illustrated by way of example, and not by way oflimitation, in the figures of the accompanying drawings in which likereference numerals refer to similar elements and in which:

FIG. 1 is a block diagram of an example of a system environment forautonomous vehicles;

FIG. 2 is a block diagram of an example of a system environment forautonomous commercial trucking vehicles;

FIG. 3 is a block diagram of an example of a system environment forautonomous commercial trucking vehicles;

FIG. 4 is a block diagram of an example of a system environment forautonomous commercial trucking vehicles;

FIG. 5 is a block diagram of an example of a LIDAR sensor system;

FIG. 6 is a block diagram of an example of an optic module of a LIDARsensor system;

FIG. 7 is a block diagram of an example of a LIDAR sensor system;

FIG. 8 is a block diagram of an example of optical components of asystem;

FIG. 9 is a block diagram of an example of a LIDAR sensor systemincluding the optical components of FIG. 8 ;

FIG. 10 is a block diagram of an example of optical components of asystem;

FIG. 11 is a block diagram of an example of a LIDAR sensor systemincluding the optical components of FIG. 10 ;

FIG. 12 is a block diagram of an example of optical components of asystem;

FIG. 13 is a block diagram of an example of optical components of asystem;

FIG. 14 is a block diagram of an example of optical components of asystem;

FIG. 15 is a block diagram of an example of a LIDAR sensor systemincluding the optical components of FIG. 14 ; and

FIG. 16 is a block diagram of an example of optical components of asystem.

DETAILED DESCRIPTION

A LIDAR sensor system can generate and transmit a light beam that anobject can reflect or otherwise scatter as a return beam correspondingto the transmitted beam. The LIDAR sensor system can receive the returnbeam, and process the return beam or characteristics thereof todetermine parameters regarding the object such as range and velocity.The LIDAR sensor system can apply various frequency or phase modulationsto the transmitted beam, which can facilitate relating the return beamto the transmitted beam in order to determine the parameters regardingthe object.

The LIDAR sensor system can include a transmitter, a receiver, and ascanner. The transmitter includes a first grating coupler and isconfigured to output a transmit beam. The receiver includes a pluralityof second grating couplers spaced from the first grating coupler. Thescanner is configured to receive the beam from the transmitter, providethe beam to an environment, receive a return beam from reflection of thetransmit beam by an object, and provide the return beam to the receiver,which can be used to determine range, velocity, and Doppler informationregarding the object, such as for controlling operation of an autonomousvehicle.

Systems and methods in accordance with the present disclosure canimplement LIDAR sensor systems in which at least one integrated chip isassembled with an array of grating couplers. The array of gratingcouplers can be spaced according to a target range from the scanner fordetecting an object. For example, the time delay between the transmitteroutputting the transmit beam and the scanner receiving the return beamfrom reflection of the transmit beam by the object can be calculatedbased on the distance, e.g., the target range, the object is from thescanner. The array of grating couplers can be spaced so as to accountfor the scanner receiving the return beam from reflection of thetransmit beam by the object after the time delay and the providing thereturn beam to the receiver. For example, the scanner can scanbi-directionally such that the location the scanner receives thetransmit beam is different, due to the time it takes for the transmitbeam to reach the object and return, e.g., the time delay, from thelocation the scanner receives the return beam from reflection of thetransmit beam. By using grating couplers for the transmitter andreceiver, LIDAR sensors systems as described herein can address suchconsiderations regarding time delays while also being made more compact.By calculating the location the receiver must be at, the gratingcouplers can all be on the single integrated chip, which can enableprocess efficiency, and enable the chip to have reduced weight relativeto LIDAR sensor systems that require separate chips for the transmitterand receiver. However, the advantages of the sensor systems describedabove are not limited to autonomous vehicles. They can be advantageousfor any type of vehicles equipped with LIDAR sensors.

1. System Environments for Autonomous Vehicles

FIG. 1 is a block diagram illustrating an example of a systemenvironment for autonomous vehicles according to some implementations.FIG. 1 depicts an example autonomous vehicle 100 within which thevarious techniques disclosed herein may be implemented. The vehicle 100,for example, may include a powertrain 102 including a prime mover 104powered by an energy source 106 and capable of providing power to adrivetrain 108, as well as a control system 110 including a directioncontrol 112, a powertrain control 114, and a brake control 116. Thevehicle 100 may be implemented as any number of different types ofvehicles, including vehicles capable of transporting people and/orcargo, and capable of traveling in various environments. Theaforementioned components 102-116 can vary widely based upon the type ofvehicle within which these components are utilized, such as a wheeledland vehicle such as a car, van, truck, or bus. The prime mover 104 mayinclude one or more electric motors and/or an internal combustion engine(among others). The energy source may include, for example, a fuelsystem (e.g., providing gasoline, diesel, hydrogen, etc.), a batterysystem, solar panels or other renewable energy source, and/or a fuelcell system. The drivetrain 108 can include wheels and/or tires alongwith a transmission and/or any other mechanical drive components toconvert the output of the prime mover 104 into vehicular motion, as wellas one or more brakes configured to controllably stop or slow thevehicle 100 and direction or steering components suitable forcontrolling the trajectory of the vehicle 100 (e.g., a rack and pinionsteering linkage enabling one or more wheels of the vehicle 100 to pivotabout a generally vertical axis to vary an angle of the rotationalplanes of the wheels relative to the longitudinal axis of the vehicle).In some implementations, combinations of powertrains and energy sourcesmay be used (e.g., in the case of electric/gas hybrid vehicles), and insome instances multiple electric motors (e.g., dedicated to individualwheels or axles) may be used as a prime mover.

The direction control 112 may include one or more actuators and/orsensors for controlling and receiving feedback from the direction orsteering components to enable the vehicle 100 to follow a desiredtrajectory. The powertrain control 114 may be configured to control theoutput of the powertrain 102, e.g., to control the output power of theprime mover 104, to control a gear of a transmission in the drivetrain108, etc., thereby controlling a speed and/or direction of the vehicle100. The brake control 116 may be configured to control one or morebrakes that slow or stop vehicle 100, e.g., disk or drum brakes coupledto the wheels of the vehicle.

Other vehicle types, including but not limited to off-road vehicles,all-terrain or tracked vehicles, construction equipment, may utilizedifferent powertrains, drivetrains, energy sources, direction controls,powertrain controls and brake controls. Moreover, in someimplementations, some of the components can be combined, e.g., wheredirectional control of a vehicle is primarily handled by varying anoutput of one or more prime movers.

Various levels of autonomous control over the vehicle 100 can beimplemented in a vehicle control system 120, which may include one ormore processors 122 and one or more memories 124, with each processor122 configured to execute program code instructions 126 stored in amemory 124. The processors(s) can include, for example, graphicsprocessing unit(s) (“GPU(s)”)) and/or central processing unit(s)(“CPU(s)”).

Sensors 130 may include various sensors suitable for collectinginformation from a vehicle's surrounding environment for use incontrolling the operation of the vehicle. For example, sensors 130 caninclude radar sensor 134, LIDAR (Light Detection and Ranging) sensor136, a 3D positioning sensors 138, e.g., any of an accelerometer, agyroscope, a magnetometer, or a satellite navigation system such as GPS(Global Positioning System), GLONASS (Globalnaya NavigazionnayaSputnikovaya Sistema, or Global Navigation Satellite System), BeiDouNavigation Satellite System (BDS), Galileo, Compass, etc. The 3Dpositioning sensors 138 can be used to determine the location of thevehicle on the Earth using satellite signals. The sensors 130 caninclude a camera 140 and/or an IMU (inertial measurement unit) 142. Thecamera 140 can be a monographic or stereographic camera and can recordstill and/or video images. The IMU 142 can include multiple gyroscopesand accelerometers capable of detecting linear and rotational motion ofthe vehicle in three directions. One or more encoders (not illustrated),such as wheel encoders may be used to monitor the rotation of one ormore wheels of vehicle 100. Each sensor 130 can output sensor data atvarious data rates, which may be different than the data rates of othersensors 130.

The outputs of sensors 130 may be provided to a set of controlsubsystems 150, including a localization subsystem 152, a planningsubsystem 156, a perception subsystem 154, and a control subsystem 158.The localization subsystem 152 can perform functions such as preciselydetermining the location and orientation (also sometimes referred to as“pose”) of the vehicle 100 within its surrounding environment, andgenerally within some frame of reference. The location of an autonomousvehicle can be compared with the location of an additional vehicle inthe same environment as part of generating labeled autonomous vehicledata. The perception subsystem 154 can perform functions such asdetecting, tracking, determining, and/or identifying objects within theenvironment surrounding vehicle 100. A machine learning model inaccordance with some implementations can be utilized in trackingobjects. The planning subsystem 156 can perform functions such asplanning a trajectory for vehicle 100 over some timeframe given adesired destination as well as the static and moving objects within theenvironment. A machine learning model in accordance with someimplementations can be utilized in planning a vehicle trajectory. Thecontrol subsystem 158 can perform functions such as generating suitablecontrol signals for controlling the various controls in the vehiclecontrol system 120 in order to implement the planned trajectory of thevehicle 100. A machine learning model can be utilized to generate one ormore signals to control an autonomous vehicle to implement the plannedtrajectory.

Multiple sensors of types illustrated in FIG. 1 can be used forredundancy and/or to cover different regions around a vehicle, and othertypes of sensors may be used. Various types and/or combinations ofcontrol subsystems may be used. Some or all of the functionality of asubsystem 152-158 may be implemented with program code instructions 126resident in one or more memories 124 and executed by one or moreprocessors 122, and these subsystems 152-158 may in some instances beimplemented using the same processor(s) and/or memory. Subsystems may beimplemented at least in part using various dedicated circuit logic,various processors, various field programmable gate arrays (“FPGA”),various application-specific integrated circuits (“ASIC”), various realtime controllers, and the like, as noted above, multiple subsystems mayutilize circuitry, processors, sensors, and/or other components.Further, the various components in the vehicle control system 120 may benetworked in various manners.

In some implementations, the vehicle 100 may also include a secondaryvehicle control system (not illustrated), which may be used as aredundant or backup control system for the vehicle 100. In someimplementations, the secondary vehicle control system may be capable offully operating the autonomous vehicle 100 in the event of an adverseevent in the vehicle control system 120, while in other implementations,the secondary vehicle control system may only have limitedfunctionality, e.g., to perform a controlled stop of the vehicle 100 inresponse to an adverse event detected in the primary vehicle controlsystem 120. In still other implementations, the secondary vehiclecontrol system may be omitted.

Various architectures, including various combinations of software,hardware, circuit logic, sensors, and networks, may be used to implementthe various components illustrated in FIG. 1 . Each processor may beimplemented, for example, as a microprocessor and each memory mayrepresent the random access memory (“RAM”) devices comprising a mainstorage, as well as any supplemental levels of memory, e.g., cachememories, non-volatile or backup memories (e.g., programmable or flashmemories), read-only memories, etc. In addition, each memory may beconsidered to include memory storage physically located elsewhere in thevehicle 100, e.g., any cache memory in a processor, as well as anystorage capacity used as a virtual memory, e.g., as stored on a massstorage device or another computer controller. One or more processorsillustrated in FIG. 1 , or entirely separate processors, may be used toimplement additional functionality in the vehicle 100 outside of thepurposes of autonomous control, e.g., to control entertainment systems,to operate doors, lights, convenience features, etc.

In addition, for additional storage, the vehicle 100 may include one ormore mass storage devices, e.g., a removable disk drive, a hard diskdrive, a direct access storage device (“DASD”), an optical drive (e.g.,a CD drive, a DVD drive, etc.), a solid state storage drive (“SSD”),network attached storage, a storage area network, and/or a tape drive,among others.

Furthermore, the vehicle 100 may include a user interface 164 to enablevehicle 100 to receive a number of inputs from and generate outputs fora user or operator, e.g., one or more displays, touchscreens, voiceand/or gesture interfaces, buttons and other tactile controls, etc.Otherwise, user input may be received via another computer or electronicdevice, e.g., via an app on a mobile device or via a web interface.

Moreover, the vehicle 100 may include one or more network interfaces,e.g., network interface 162, suitable for communicating with one or morenetworks 170 (e.g., a Local Area Network (“LAN”), a wide area network(“WAN”), a wireless network, and/or the Internet, among others) topermit the communication of information with other computers andelectronic device, including, for example, a central service, such as acloud service, from which the vehicle 100 receives environmental andother data for use in autonomous control thereof. Data collected by theone or more sensors 130 can be uploaded to a computing system 172 viathe network 170 for additional processing. In some implementations, atime stamp can be added to each instance of vehicle data prior touploading.

Each processor illustrated in FIG. 1 , as well as various additionalcontrollers and subsystems disclosed herein, generally operates underthe control of an operating system and executes or otherwise relies uponvarious computer software applications, components, programs, objects,modules, data structures, etc., as will be described in greater detailbelow. Moreover, various applications, components, programs, objects,modules, etc. may also execute on one or more processors in anothercomputer coupled to vehicle 100 via network 170, e.g., in a distributed,cloud-based, or client-server computing environment, whereby theprocessing required to implement the functions of a computer program maybe allocated to multiple computers and/or services over a network.

In general, the routines executed to implement the variousimplementations described herein, whether implemented as part of anoperating system or a specific application, component, program, object,module or sequence of instructions, or even a subset thereof, will bereferred to herein as “program code”. Program code can include one ormore instructions that are resident at various times in various memoryand storage devices, and that, when read and executed by one or moreprocessors, perform the steps necessary to execute steps or elementsembodying the various aspects of the present disclosure. Moreover, whileimplementations have and hereinafter will be described in the context offully functioning computers and systems, it will be appreciated that thevarious implementations described herein are capable of beingdistributed as a program product in a variety of forms, and thatimplementations can be implemented regardless of the particular type ofcomputer readable media used to actually carry out the distribution.

Examples of computer readable media include tangible, non-transitorymedia such as volatile and non-volatile memory devices, floppy and otherremovable disks, solid state drives, hard disk drives, magnetic tape,and optical disks (e.g., CD-ROMs, DVDs, etc.) among others.

In addition, various program code described hereinafter may beidentified based upon the application within which it is implemented ina specific implementation. Any particular program nomenclature thatfollows is used merely for convenience, and thus the present disclosureshould not be limited to use solely in any specific applicationidentified and/or implied by such nomenclature. Furthermore, given thetypically endless number of manners in which computer programs may beorganized into routines, procedures, methods, modules, objects, and thelike, as well as the various manners in which program functionality maybe allocated among various software layers that are resident within atypical computer (e.g., operating systems, libraries, API's,applications, applets, etc.), the present disclosure is not limited tothe specific organization and allocation of program functionalitydescribed herein.

2. LIDAR for Automotive Applications

A truck can include a LIDAR system (e.g., vehicle control system 120 inFIG. 1 , LIDAR sensor system 500 in FIG. 5 , among others describedherein). In some implementations, the LIDAR sensor system 500 can usefrequency modulation to encode an optical signal and scatter the encodedoptical signal into free-space using optics. By detecting the frequencydifferences between the encoded optical signal and a returned signalreflected back from an object, the frequency modulated (FM) LIDAR sensorsystem can determine the location of the object and/or precisely measurethe velocity of the object using the Doppler effect. In someimplementations, an FM LIDAR sensor system may use a continuous wave(referred to as, “FMCW LIDAR”) or a quasi-continuous wave (referred toas, “FMQW LIDAR”). In some implementations, the LIDAR sensor system canuse phase modulation (PM) to encode an optical signal and scatters theencoded optical signal into free-space using optics.

In some instances, an object (e.g., a pedestrian wearing dark clothing)may have a low reflectivity, in that it only reflects back to thesensors (e.g., sensors 130 in FIG. 1 ) of the FM or PM LIDAR sensorsystem a low amount (e.g., 10% or less) of the light that hit theobject. In other instances, an object (e.g., a shiny road sign) may havea high reflectivity (e.g., above 10%), in that it reflects back to thesensors of the FM LIDAR sensor system a high amount of the light thathit the object.

Regardless of the object's reflectivity, an FM LIDAR sensor system maybe able to detect (e.g., classify, recognize, discover, etc.) the objectat greater distances (e.g., 2×) than a conventional LIDAR sensor system.For example, an FM LIDAR sensor system may detect a low reflectivelyobject beyond 300 meters, and a high reflectivity object beyond 400meters.

To achieve such improvements in detection capability, the FM LIDARsensor system may use sensors (e.g., sensors 130 in FIG. 1 ). In someimplementations, these sensors can be single photon sensitive, meaningthat they can detect the smallest amount of light possible. While an FMLIDAR sensor system may, in some applications, use infrared wavelengths(e.g., 950 nm, 1550 nm, etc.), it is not limited to the infraredwavelength range (e.g., near infrared: 800 nm-1500 nm; middle infrared:1500 nm-5600 nm; and far infrared: 5600 nm-1,000,000 nm). By operatingthe FM or PM LIDAR sensor system in infrared wavelengths, the FM or PMLIDAR sensor system can broadcast stronger light pulses or light beamsthan conventional LIDAR sensor systems.

Thus, by detecting an object at greater distances, an FM LIDAR sensorsystem may have more time to react to unexpected obstacles. Indeed, evena few milliseconds of extra time could improve response time andcomfort, especially with heavy vehicles (e.g., commercial truckingvehicles) that are driving at highway speeds.

The FM LIDAR sensor system can provide accurate velocity for each datapoint instantaneously. In some implementations, a velocity measurementis accomplished using the Doppler effect which shifts frequency of thelight received from the object based at least one of the velocity in theradial direction (e.g., the direction vector between the object detectedand the sensor) or the frequency of the laser signal. For example, forvelocities encountered in on-road situations where the velocity is lessthan 100 meters per second (m/s), this shift at a wavelength of 1550nanometers (nm) amounts to the frequency shift that is less than 130megahertz (MHz). This frequency shift is small such that it is difficultto detect directly in the optical domain. However, by using coherentdetection in FMCW, PMCW, or FMQW LIDAR sensor systems, the signal can beconverted to the RF domain such that the frequency shift can becalculated using various signal processing techniques. This enables theautonomous vehicle control system to process incoming data faster.

Instantaneous velocity calculation also makes it easier for the FM LIDARsensor system to determine distant or sparse data points as objectsand/or track how those objects are moving over time. For example, an FMLIDAR sensor (e.g., sensors 130 in FIG. 1 ) may only receive a fewreturns (e.g., hits) on an object that is 300 m away, but if thosereturn give a velocity value of interest (e.g., moving towards thevehicle at >70 mph), then the FM LIDAR sensor system and/or theautonomous vehicle control system may determine respective weights toprobabilities associated with the objects.

Faster identification and/or tracking of the FM LIDAR sensor systemgives an autonomous vehicle control system more time to maneuver avehicle. A better understanding of how fast objects are moving alsoallows the autonomous vehicle control system to plan a better reaction.

The FM LIDAR sensor system can have less static compared to conventionalLIDAR sensor systems. That is, the conventional LIDAR sensor systemsthat are designed to be more light-sensitive typically perform poorly inbright sunlight. These systems also tend to suffer from crosstalk (e.g.,when sensors get confused by each other's light pulses or light beams)and from self-interference (e.g., when a sensor gets confused by its ownprevious light pulse or light beam). To overcome these disadvantages,vehicles using the conventional LIDAR sensor systems often need extrahardware, complex software, and/or more computational power to managethis “noise.”

In contrast, FM LIDAR sensor systems do not suffer from these types ofissues because each sensor is specially designed to respond only to itsown light characteristics (e.g., light beams, light waves, lightpulses). If the returning light does not match the timing, frequency,and/or wavelength of what was originally transmitted, then the FM sensorcan filter (e.g., remove, ignore, etc.) out that data point. As such, FMLIDAR sensor systems produce (e.g., generates, derives, etc.) moreaccurate data with less hardware or software requirements, enablingsmoother driving.

The FM LIDAR sensor system can be easier to scale than conventionalLIDAR sensor systems. As more self-driving vehicles (e.g., cars,commercial trucks, etc.) show up on the road, those powered by an FMLIDAR sensor system likely will not have to contend with interferenceissues from sensor crosstalk. Furthermore, an FM LIDAR sensor systemuses less optical peak power than conventional LIDAR sensors. As such,some or all of the optical components for an FM LIDAR can be produced ona single chip, which produces its own benefits, as discussed herein.

2.1 Commercial Trucking

FIG. 2 is a block diagram illustrating an example of a systemenvironment for autonomous commercial trucking vehicles, according tosome implementations. The environment 100B includes a commercial truck102B for hauling cargo 106B. In some implementations, the commercialtruck 102B may include vehicles configured to long-haul freighttransport, regional freight transport, intermodal freight transport(i.e., in which a road-based vehicle is used as one of multiple modes oftransportation to move freight), and/or any other road-based freighttransport applications. In some implementations, the commercial truck102B may be a flatbed truck, a refrigerated truck (e.g., a reefertruck), a vented van (e.g., dry van), a moving truck, etc. In someimplementations, the cargo 106B may be goods and/or produce. In someimplementations, the commercial truck 102B may include a trailer tocarry the cargo 106B, such as a flatbed trailer, a lowboy trailer, astep deck trailer, an extendable flatbed trailer, a sidekit trailer,etc.

The environment 100B includes an object 110B (shown in FIG. 2 as anothervehicle) that is within a distance range that is equal to or less than30 meters from the truck.

The commercial truck 102B may include a LIDAR sensor system 104B (e.g.,an FM LIDAR sensor system, vehicle control system 120 in FIG. 1 , LIDARsensor system 500 in FIG. 5 ) for determining a distance to the object110B and/or measuring the velocity of the object 110B. Although FIG. 2shows that one LIDAR sensor system 104B is mounted on the front of thecommercial truck 102B, the number of LIDAR sensor system and themounting area of the LIDAR sensor system on the commercial truck are notlimited to a particular number or a particular area. The commercialtruck 102B may include any number of LIDAR sensor systems 104B (orcomponents thereof, such as sensors, modulators, coherent signalgenerators, etc.) that are mounted onto any area (e.g., front, back,side, top, bottom, underneath, and/or bottom) of the commercial truck102B to facilitate the detection of an object in any free-space relativeto the commercial truck 102B.

As shown, the LIDAR sensor system 104B in environment 100B may beconfigured to detect an object (e.g., another vehicle, a bicycle, atree, street signs, potholes, etc.) at short distances (e.g., 30 metersor less) from the commercial truck 102B.

FIG. 3 is a block diagram illustrating an example of a systemenvironment for autonomous commercial trucking vehicles, according tosome implementations. The environment 100C includes the same components(e.g., commercial truck 102B, cargo 106B, LIDAR sensor system 104B,etc.) that are included in environment 100B.

The environment 100C includes an object 110C (shown in FIG. 3 as anothervehicle) that is within a distance range that is (i) more than 30 metersand (ii) equal to or less than 150 meters from the commercial truck102B. As shown, the LIDAR sensor system 104B in environment 100C may beconfigured to detect an object (e.g., another vehicle, a bicycle, atree, street signs, potholes, etc.) at a distance (e.g., 100 meters)from the commercial truck 102B.

FIG. 4 is a block diagram illustrating an example of a systemenvironment for autonomous commercial trucking vehicles, according tosome implementations. The environment 100D includes the same components(e.g., commercial truck 102B, cargo 106B, LIDAR sensor system 104B,etc.) that are included in environment 100B.

The environment 100D includes an object 110D (shown in FIG. 4 as anothervehicle) that is within a distance range that is more than 150 metersfrom the commercial truck 102B. As shown, the LIDAR sensor system 104Bin environment 100D may be configured to detect an object (e.g., anothervehicle, a bicycle, a tree, street signs, potholes, etc.) at a distance(e.g., 300 meters) from the commercial truck 102B.

In commercial trucking applications, it is important to effectivelydetect objects at all ranges due to the increased weight and,accordingly, longer stopping distance required for such vehicles. FMLIDAR sensor systems (e.g., FMCW and/or FMQW systems) or PM LIDAR sensorsystems are well-suited for commercial trucking applications due to theadvantages described above. As a result, commercial trucks equipped withsuch systems may have an enhanced ability to move both people and goodsacross short or long distances. In various implementations, such FM orPM LIDAR sensor systems can be used in semi-autonomous applications, inwhich the commercial truck has a driver and some functions of thecommercial truck are autonomously operated using the FM or PM LIDARsensor system, or fully autonomous applications, in which the commercialtruck is operated entirely by the FM or LIDAR sensor system, alone or incombination with other vehicle systems.

3. LIDAR Sensor Systems

FIG. 5 depicts an example of a LIDAR sensor system 500. The LIDAR sensorsystem 500 can be used to determine parameters regarding objects, suchas range and velocity, and output the parameters to a remote system. Forexample, the LIDAR sensor system 500 can output the parameters for useby a vehicle controller that can control operation of a vehicleresponsive to the received parameters (e.g., vehicle controller 598) ora display that can present a representation of the parameters. The LIDARsensor system 500 can be a coherent detection system. The LIDAR sensorsystem 500 can be used to implement various features and components ofthe systems described with reference to FIGS. 1-4 . The LIDAR sensorsystem 500 can include components for performing various detectionapproaches, such as to be operated as an amplitude modular LIDAR systemor a coherent LIDAR system. The LIDAR sensor system 500 can be used toperform time of flight range determination. In some implementations,various components or combinations of components of the LIDAR sensorsystem 500, such as laser source 504 and modulator 514, can be in a samehousing, provided in a same circuit board or other electronic component,or otherwise integrated. In some implementations, various components orcombinations of components of the LIDAR sensor system 500 can beprovided as separate components, such as by using optical couplings(e.g., optical fibers) for components that generate and/or receiveoptical signals, such as light beams, or wired or wireless electronicconnections for components that generate and/or receive electrical(e.g., data) signals. Various components of the LIDAR sensor system 500can be arranged with respect to one another such that light (e.g., beamsof light) between the components is directed through free space, such asa space provided by an air (or vacuum) gap, a space that is not throughan optical fiber, a space that is free of structural components around apath along which the light is directed (e.g., an empty space at least onthe order of millimeters away from a direct line path between thecomponents; an empty space of a size greater than an expected beam widthof the light, such as where the light is a collimated beam), or variouscombinations thereof.

The LIDAR sensor system 500 can include a laser source 504 thatgenerates and emits a beam 506, such as a carrier wave light beam. Asplitter 508 can split the beam 506 into a beam 510 and a reference beam512 (e.g., reference signal). In some implementations, any suitableoptical, electronic, or opto-electronic elements can be used to providethe beam 510 and the reference beam 512 from the laser source 504 toother elements.

A modulator 514 can modulate one or more properties of the input beam510 to generate a beam 516 (e.g., target beam). In some implementations,the modulator 514 can modulate a frequency of the input beam 510 (e.g.,optical frequency corresponding to optical wavelength, where c=λv, wherec is the speed of light, λ is the wavelength, and v is the frequency).For example, the modulator 514 can modulate a frequency of the inputbeam 510 linearly such that a frequency of the beam 516 increases ordecreases linearly over time. As another example, the modulator 514 canmodulate a frequency of the input beam 510 non-linearly (e.g.,exponentially). In some implementations, the modulator 514 can modulatea phase of the input beam 510 to generate the beam 516. However, themodulation techniques are not limited to the frequency modulation andthe phase modulation. Any suitable modulation techniques can be used tomodulate one or more properties of a beam. Returning to FIG. 5 , themodulator 514 can modulate the beam 510 subsequent to splitting of thebeam 506 by the splitter 508, such that the reference beam 512 isunmodulated, or the modulator 514 can modulate the beam 506 and providea modulated beam to the splitter 508 for the splitter 508 to split intoa target beam and a reference beam.

The beam 516, which is used for outputting a transmitted signal, canhave most of the energy of the beam 506 outputted by the laser source504, while the reference beam 512 can have significantly less energy,yet sufficient energy to enable mixing with a return beam 548 (e.g.,returned light) scattered from an object. The reference beam 512 can beused as a local oscillator (LO) signal. The reference beam 512 passesthrough a reference path and can be provided to a mixer 560. Anamplifier 520 can amplify the beam 516 to output a beam 522.

The LIDAR sensor system 500 can include an optic module 524, which canreceive the beam 522. The optic module 524 can be a free space optic.For example, the optic module 524 can include one or more optics (e.g.,lenses, mirrors, waveguides, grating couplers, prisms, waveplates)arranged to have a gap (e.g., air gap) between the one or more optics,allowing for free space transmission of light (e.g., rather than alllight being coupled between optics by fibers). The optic module 524 canperform functions such as collimating, filtering, and/or polarizing thebeam 522 to output a beam 530 to optics 532 (e.g., scanning optics).

Referring to FIG. 6 , the optic module 524 can include at least onecollimator 604 and at least one circulator 608. For example, thecirculator 608 can be between the collimator 604 and the optics 532 ofFIG. 5 . The circulator 608 can receive a collimated beam 612 outputtedby the collimator 604 and output a beam 616 (e.g., the beam 530 depictedin FIG. 5 ) to the optics 532. In some implementations, the circulator608 can be between the laser source 504 and the collimator 604. At leastone of the collimator 604 or the circulator 608 can be free space optics(and can be coupled with one another in free space), such as by beingoptically coupled via air gaps rather than optical fibers.

Referring further to FIG. 5 , the optic module 524 can receive returnbeam 548 from the optics 532 and provide the return beam 548 to themixer 560. The optics 532 can be scanning optics, such as one or moresteering mirrors or polygon reflectors or deflectors to adjust the angleof received beams relative to outputted beams based on the orientationof outer surfaces (e.g., facets) of the optics relative to the receivedbeam, or solid-state components (e.g., phased arrays, electro-opticcrystals) configured to modify the direction of received light.

The optics 532 can define a field of view 544 that corresponds to anglesscanned (e.g., swept) by the beam 542 (e.g., a transmitted beam). Forexample, the beam 542 can be scanned in the particular plane, such as anazimuth plane or elevation plane (e.g., relative to an object to whichthe LIDAR sensor system 500 is coupled, such as an autonomous vehicle).The optics 532 can be oriented so that the field of view 544 sweeps anazimuthal plane relative to the optics 532.

At least one motor 540 can be coupled with the optics 532 to control atleast one of a position or an orientation of the optics 532 relative tothe beam 530. For example, where the optics 532 include a mirror,reflector, or deflector, the motor 540 can rotate the optics 532relative to an axis 534 (e.g., an axis orthogonal to the frame ofreference depicted in FIG. 5 ) so that surfaces of the optics 532 atwhich the beam 530 is received vary in angle or orientation relative tothe beam 530, causing the beam 542 to be varied in angle or direction asthe beam 542 is outputted from the optics 532.

The beam 542 can be outputted from the optics 532 and reflected orotherwise scattered by an object (not shown) as a return beam 548 (e.g.,return signal). The return beam 548 can be received on a reception path,which can include the circulator 608, and provided to the mixer 560.

The mixer 560 can be an optical hybrid, such as a 90 degree opticalhybrid. The mixer 560 can receive the reference beam 512 and the returnbeam 548, and mix the reference beam 512 and the return beam 548 tooutput a signal 564 responsive to the reference beam 512 and the returnbeam 548. The signal 564 can include an in-phase (I) component 568 and aquadrature (Q) component 572.

The LIDAR sensor system 500 can include a receiver 576 that receives thesignal 564 from the mixer 560. The receiver 576 can generate a signal580 responsive to the signal 564, which can be an electronic (e.g.,radio frequency) signal. The receiver 576 can include one or morephotodetectors that output the signal 580 responsive to the signal 564.

The LIDAR sensor system 500 can include a processing system 590, whichcan be implemented using features of the vehicle control system 120described with reference to FIG. 1 . The processing system 590 canprocess data received regarding the return beam 548, such as the signal580, to determine parameters regarding the object such as range andvelocity. The processing system 590 can include a scanner controller 592that can provide scanning signals to control operation of the optics532, such as to control the motor 540 to cause the motor 540 to rotatethe optics 532 to achieve a target scan pattern, such as a sawtooth scanpattern or step function scan pattern. The processing system 590 caninclude a Doppler compensator 594 that can determine the sign and sizeof a Doppler shift associated with processing the return beam 548 and acorrected range based thereon along with any other corrections. Theprocessing system 590 can include a modulator controller 596 that cansend one or more electrical signals to drive the modulator 514.

The processing system 590 can include or be communicatively coupled witha vehicle controller 598 to control operation of a vehicle for which theLIDAR sensor system 500 is installed (e.g., to provide complete orsemi-autonomous control of the vehicle). For example, the vehiclecontroller 598 can be implemented by at least one of the LIDAR sensorsystem 500 or control circuitry of the vehicle. The vehicle controller598 can control operation of the vehicle responsive to at least one of arange to the object or a velocity of the object determined by theprocessing system 590. For example, the vehicle controller 598 cantransmit a control signal to at least one of a steering system or abraking system of the vehicle to control at least one of speed ordirection of the vehicle.

3.1 LIDAR Sensor System Including Grating Couplers for MultipleDirection Reception

FIG. 7 depicts a block diagram of an example of a LIDAR sensor system700. The LIDAR sensor system 700 can incorporate features of the LIDARsensor system 500 and optic module 524 described with reference to FIGS.5 and 6 , respectively. The LIDAR sensor system 700 can facilitatepitch-catch compensation, i.e. accounting for time delays or otheroffsets resulting from the round-trip path of the transmit beamoutputted from the LIDAR sensor system 700, reflected or otherwisescattered by object(s), and then returned as the return beam to theLIDAR sensor system 700 for detection and processing, which mightotherwise affect characteristics of the LIDAR sensor system 700 such assignal-to-noise ratio.

The LIDAR sensor system 700 can include a chip 705 on which variouscomponents of the LIDAR sensor system 700, including transmitter 710 andreceiver 712, can be provided. For example, the chip 705 can be aphotonic integrated chip, such that various components of the LIDARsensor system 700 for generating, modulating, and processing opticalsignals and performing photonic operations are implemented by the chip705. The chip 705 can be a semiconductor circuit chip. The chip 705 canbe made from at least one III-V semiconductor material. For example, thechip 705 can be made from a silicon material or pure silicon. The chip705 can be made from silicon nitride. The chip 705 can be made fromaluminum nitride. The chip 705 can be made from silicon nitride and puresilicon.

The LIDAR sensor system 700 includes at least one transmitter 710. Thetransmitter 710 can receive a beam (e.g., various beams described withreference to FIGS. 5 and 6 ) and output transmit beam 735 withparticular characteristics such as direction, polarization, or variouscombinations thereof.

The transmitter 710 can include at least one grating coupler 715 (e.g.,a first grating coupler). The grating coupler 715 can be a structurehaving a plurality of spaced apart channels, such as parallel channels,which may have various shapes of the same or differing sizes. Thegrating coupler 715 can be a structure formed by etching on the chip705. The grating coupler 715 can be a structure formed by deposition ofmaterial on the chip 705.

The grating coupler 715 can be configured to couple light off of thechip 705, such as into free space away from the chip 705. For example,the grating coupler 715 can couple light off of the chip 705 in atwo-dimensional pattern, such as a two-dimensional polarization. Assuch, the grating coupler 715 can output a transmit beam 735, such asbased on a beam outputted by laser source 504.

The grating coupler 715 can output the transmit beam 735 to have atransmit polarization 795. For example, various components upstream ordownstream of the grating coupler 715 (e.g., optic module 524) can beused to control the polarization of the transmit beam 735.

The LIDAR sensor system 700 can include at least one scanner 740, e.g.,a steering mirror. For example, referring briefly to FIG. 5 , thescanner 740 can be coupled with the motor 540, so that the scanner 740can be rotated relative to the direction along which the transmit beam735 is directed towards the scanner 740.

The scanner 740 can scan bi-directionally. For example, the scanner 740can scan in a first direction 760 and a second direction 765 (e.g.,relative to axis 534 described with reference to FIG. 5 ). The scanner740 can receive the transmit beam 735 from the transmitter 710 anddirect the transmit beam 735 towards the environment around the LIDARsensor system 700. As depicted in FIG. 7 , an object 702 can be presentin the environment. The scanner 740 can receive a return beam 755 fromreflection or scattering of the transmit beam 735 by the object 702. Inthe time it takes for the transmit beam 735 to reach the object 702 andthe return beam 755 to return from the object 702 to the scanner 740,the scanner 740 may have rotated by a particular angle, as discussedmore below. The scanner 740 can provide the return beam 755 to thereceiver 712.

The receiver 712 can include a plurality of grating couplers. Forexample, the receiver 712 can include a grating coupler 725 and agrating coupler 730. The grating couplers 725, 730 can be provided orformed in a manner similar to or identical to the grating coupler 715.The grating couplers 715, 725, 730 can be arranged in an array on thechip 705 (e.g., at least two parallel spaced-apart lines can extendthrough each of the grating couplers 715, 725, 730). The gratingcouplers 715, 725, 730 can be arranged in a focal plane of at least oneof the scanner 740 or one or more optical components between the gratingcouplers 715, 725, 730 and the scanner 740.

The grating couplers 725, 730 can be spaced from the grating coupler715. For example, the grating coupler 725 can be spaced from the gratingcoupler 715 by a first spacing. The first spacing can be associated witha first target range from the scanner 740 for detecting the object 702.For example, the first target range can be within a range of distancesfrom the scanner 740 for which an expected signal to noise ratio ofdetermining at least one of range to or velocity of the object 702 isgreater than a threshold signal to noise ratio. The first spacing can beproportional to a mode field diameter of the grating coupler 715 and/orthe grating couplers 725, 730, such as to be between about 1 time and 3times the mode field diameter. The first spacing can be between about 8micrometers (μm) and 24 μm. The first spacing can be between about 12micrometers (μm) and about 16 μm. For example, the grating coupler 725can be spaced from the grating coupler 715 by about 14 μm.

The grating coupler 730 can be spaced from the grating coupler 715 by asecond spacing. The second spacing can be associated with a secondtarget range from the scanner 740. The second target range can begreater than the first target range. The second spacing can be betweenabout 10 μm and about 20 μm. For example, the grating coupler 730 can bespaced from the grating coupler 715 by about 12 micrometers.

The grating couplers 725, 730 can receive the return beam 755 providedby the scanner 740. The grating couplers 725, 730 can couple light,e.g., the return beam 755, from free space onto the chip 705. Aspreviously mentioned, the scanner 740 can rotate in the time it takesfor the transmit beam 735 to travel to the object 702 and be returned asthe return beam 755 to the receiver 712, which can result in an angulardisplacement of the return beam 755 in the direction the scanner 740 isscanning. The angular displacement can manifest as a translation in thefocal plane when the return beam 755 is provided to the receiver 712.The translation can be referred to as focal plane drift. Since thegrating couplers 725, 730 can couple light on the chip 705 and aredistinct and spatially separated, the grating couplers 725, 730 can beprovided for two directions of focal plane drift. Additionally, thetranslational distance can be optimized for a target time for thetransmit beam 735 to travel to the object 702 and the return beam 755 toreturn from the object 702 to the receiver 712, and thus a specificrange to the object 702 (because the scan velocity of the transmit beam735 and the return beam 755 is known).

The return beam 755 can have components associated with variouspolarizations, such as based on how the transmit beam 735 is outputtedand/or passed through devices such as optic module 524. As such, thescanner 740 can provide a first component 770 of the return beam 755,which can be associated with a first polarization 780, and the gratingcoupler 725 can receive the first component 770 of the return beam 755.The scanner 740 can provide a second component 775 of the return beam755 associated with a second polarization 785, and the grating coupler730 can receive the second component 775.

The first polarization 780 can be different than the second polarization785. The transmit polarization 795 can be the same as the firstpolarization 780. For example, the grating coupler 715 can output thetransmit beam 735 at the first polarization 780. The grating couplers725, 730 can receive the return beam 755 at the first polarization 780or at the second polarization 785. The second polarization 785 can beorthogonal to the first polarization 780.

The grating couplers 725, 730 can be configured to only receive a singlepolarization of a beam, e.g., light. The grating couplers 725, 730 canreceive light of different polarizations. For example, the gratingcoupler 725 can receive light of the same polarization as that of thetransmit beam 735 and the grating coupler 730 can receive light of apolarization orthogonal to the polarization of the transmit beam 735.The grating couplers 725, 730 can be configured to receive the samepolarization of light as each other. For example, the grating couplers725, 730 can receive light (only) of a polarization orthogonal to thepolarization of the transmit beam 735, as depicted in FIG. 7 , or thatis the same as the polarization of the transmit beam 735.

The receiver 712 can output at least one signal based on the firstcomponent 770 of the return beam 755 received by the grating coupler 725and based on the second component 775 of the return beam 755 received bythe grating coupler 730. The at least one signal outputted by thereceiver 712 can be used by various systems described herein, such asthe vehicle control system 120, to determine at least one of a range toor a velocity of the object 702, such as to control operation of anautonomous vehicle responsive to the at least one of the range or thevelocity.

FIG. 8 is a block diagram of an example of optical components of asystem 800. The system 800 can include components of and/or be used toimplement various LIDAR sensor systems described herein, such as thetransmitter 710 and the receiver 712. For example, the system 800 can beused to implement a receiver of a single polarization, and a switchedlocal oscillator.

As depicted in FIG. 8 , the system 800 can include a transmit antenna810, which can be implemented by the grating coupler 715 of thetransmitter 710. For example, the transmit antenna 810 can be an opticalantenna integrated onto the chip 705. The transmit antenna 810 cancouple the transmit beam 735 into free space. The transmit antenna 810can be oriented at an angle relative to a surface on which the transmitantenna 810 is provided corresponding to the polarization of thetransmit beam 735.

The system 800 can include a local oscillator 815. The local oscillator815 can output local oscillator (LO) signals. For example, the localoscillator 815 can actively switch the LO signal between at least twomixers, as discussed more below, based on the scanning direction of thescanner 740. For example, the local oscillator 815 can output a first LOsignal and a second LO signal. The LO signals can be similar to or thesame as reference beam 512. For example, the local oscillator 815 cantransmit the first LO signal, e.g., a reference beam 820. The localoscillator 815 can transmit the second LO signal, e.g., a reference beam830. By the local oscillator 815 switching the LO signal, the amount ofpower required by the local oscillator 815 can be reduced.

The system 800 can include a receive antenna 825 of the receiver 712.The receive antenna 825 can be implemented by the grating coupler 725 ofthe receiver 712. For example, the receive antenna 825 can be an opticalantenna integrated onto the chip 705. The receive antenna 825 can couplethe first component 770 of the return beam 755 onto the chip 705 fromfree space. The receive antenna 825 can be oriented at an angle relativeto a surface on which the receive antenna 825 is provided correspondingto the first polarization 780 of the first component 770 of the returnbeam 755.

The receive antenna 825 can receive the return beam 755. For example,the receive antenna 825 can receive the first component 770 of thereturn beam 755. As such, the receive antenna 825 can be oriented at thesame polarization as the first component 770 of the return beam 755. Forexample, the receive antenna 825 can have the same polarization as thefirst polarization 780. The receive antenna 825 can provide the firstcomponent 770 of the return beam 755 to other elements of the system800, as discussed more below.

The system 800 can include a receive antenna 835 of the receiver 712.The receive antenna 835 can be implemented by the grating coupler 730 ofthe receiver 712. For example, the receive antenna 835 can be an opticalantenna integrated onto the chip 705. The receive antenna 835 can couplethe second component 775 of the return beam 755 onto the chip 705 fromfree space. The receive antenna 835 can be oriented at an angle relativeto a surface on which the receive antenna 835 is provided correspondingto the second polarization 785 of the second component 775 of the returnbeam 755.

The receive antenna 835 can receive the return beam 755. For example,the receive antenna 835 can receive the second component 775 of thereturn beam 755. As such, the receive antenna 835 can be oriented at thesame polarization as the second component 775 of the return beam 755.For example, the receive antenna 835 can have the same polarization asthe second polarization 785. The receive antenna 835 can provide thesecond component 775 of the return beam 755 to other elements of thesystem 800, as discussed more below.

The system 800 can include at least one mixer. The mixer can be similarto or the same as the mixer 560. For example, the system 800 can includea mixer 840, which functions similar to the mixer 560. For example, thesystem 800 can include a mixer 845, which functions similar to the mixer560. The mixers 840, 845 can each be a 2×2 optical mixer. The mixers840, 845 can each be an optical hybrid. For example, the mixers 840, 845can each be a 90 degree optical hybrid. For example, the mixers 840, 845can each be a 2×4 optical hybrid.

The mixers 840, 845 can receive signals. For example, the mixer 840 canreceive the reference beam 820, e.g., the first LO signal. For example,the mixer 840 can receive the first component 770 of the return beam 755from the receive antenna 825. For example, the mixer 845 can receive thereference beam 830, e.g., the second LO signal. For example, the mixer845 can receive the second component 775 of the return beam 755 from thereceive antenna 835.

The mixers 840, 845 can each output a signal. For example, the outputsignals can be based on the signals that each of the mixers 840, 845received from the receive antennas 825, 835. For example, the outputsignals can be based on the signals that each of the mixers 840, 845received from the local oscillator 815. For example, the mixers 840, 845can output signals responsive to the return beam 755 and the referencebeams 820, 830. For example, the mixers 840, 845 can mix the return beam755 and the reference beams 820, 830 and each output a signal. The mixer840 can output a signal 850. The signal 850 can be responsive to andbased on the first component 770 of the return beam 755 and thereference beam 820. The mixer 845 can output a signal 855. The signal855 can be responsive to and based on the second component 775 of thereturn beam 755 and the reference beam 830. The mixers 840, 845 canprovide the signals 850, 855 to the grating couplers 725, 730,respectively, such as for the grating couplers 725, 730 to provide thecomponents 770, 775 of the return beam 755 to optical detection devices,such as one or more photodetectors of the receiver 712.

FIG. 9 is a block diagram of an example of a LIDAR sensor system 900including the optical components of FIG. 8 . The LIDAR sensor system 900can incorporate features of the LIDAR sensor system 500 and optic module524 described with reference to FIGS. 5 and 6 , respectively. The LIDARsensor system 900 can facilitate pitch-catch compensation, includingaccounting for time delays or other offsets resulting from theround-trip path of the transmit beam outputted from the LIDAR sensorsystem 900, reflected or otherwise scattered by object(s), and thenreturned as the return beam to the LIDAR sensor system 900 for detectionand processing, which might otherwise affect characteristics of theLIDAR sensor system 900 such as signal-to-noise ratio.

The LIDAR sensor system 900 can include the grating coupler 715configured to output the transmit beam 735. The LIDAR sensor system 900can include the scanner 740 configured to receive the transmit beam 735from the transmitter 710, provide the transmit beam 735 to theenvironment, and receive the return beam 755 of reflection of thetransmit beam 735 from the object 702. The LIDAR sensor system 900 caninclude the grating coupler 725 and the grating coupler 730. The gratingcoupler 725 can receive the first component 770 of the return beam 755at the first polarization 780. The grating coupler 730 can receive thesecond component 775 of the return beam 755 at the second polarization785.

The first polarization 780 can be the same as the second polarization785. The transmit polarization 795 can be different than the firstpolarization 780 and the second polarization 785. For example, thegrating coupler 715 can output the transmit beam 735 at the transmitpolarization 795 and the grating couplers 725, 730 can receive thecomponents 770, 775 of the return beam 755 with the polarizations 780,785 each orthogonal to the transmit polarization 795.

The LIDAR sensor system 900 can include a displacer 905. The transmitbeam 735 can pass unaffected through the displacer 905. The displacer905 can be a birefringent displacer such that the displacer 905 has twodifferent refractive indices. The displacer 905 can displace the returnbeam 755. For example, the displacer 905 can displace the return beam755 in the opposite polarization to the transmit beam 735 by a fixedamount. For example, the displacer 905 can displace the return beam 755to the right, e.g., relative to the orientation of the array duringoperation, of the transmit antenna 810 upon receive. The receiveantennas 825, 835 are aligned with the polarizations 780, 785 of thecomponents 770, 775 of the return beam 755. The receive antennas 825,835 are located on either side of the displaced return beam 755 suchthat they compensate for the focal plane drift, discussed above, at thespecific target distance, e.g., the range of the object 702 to thescanner 740.

The LIDAR sensor system 900 can include optic module 524 (e.g.,collimator 604 of optic module 524). The collimator 604 can bepositioned between the transmitter 710 and the scanner 740. The transmitbeam 735 can pass unaffected through the collimator 604. For example,the collimator 604 can be configured to provide the transmit beam 735 tothe scanner 740. The collimator 604 can be configured to collimate thetransmit beam 735. The collimator 604 can be configured to provide thecollimated beam 910 to other components of the LIDAR sensor system 900,as discussed more below. For example, the collimator 604 can beconfigured to provide the collimated beam 910 to the scanner 740.

The LIDAR sensor system 900 can include a wave plate 915. The wave plate915 can be made from a birefringent material, e.g., quartz or a plastic,for which the index of refraction can be different for variouspolarizations of light along at least one particular axis through thematerial. The wave plate 915 can be a quarter wave plate. For example,with the wave plate 915 being a quarter wave plate, the wave plate 915can convert linearly polarized light into circularly polarized light.For example, the wave plate 915 can convert the transmit beam 735 fromlinear to circular polarization (e.g., left or right circular) as thetransmit beam 735 is outputted from the transmitter 710. The wave plate915 can convert the return beam 755 (e.g., the return beam 755 havingbeen reflected by a polarization maintaining target) to an oppositecircular polarization orthogonal to that of the transmit beam 735 (e.g.,left to right or vice versa) to be displaced by the displacer 905.

FIG. 10 is a block diagram of an example of optical components of asystem 1000. The system 1000 can include components of and/or be used toimplement various LIDAR sensor systems described herein, such as thetransmitter 710 and the receiver 712. For example, the system 1000 canbe used to implement a receiver of a single polarization, and a switchedlocal oscillator.

The system 1000 is similar to the system 800. However, the polarizationsof the receive antennas 825, 835 are aligned with the polarization ofthe transmit antenna 810. As mentioned above, the transmit antenna 810can have the same polarization as the transmit polarization 795, thereceive antenna 825 can have the same polarization as the firstpolarization 780, and the receive antenna 835 can have the samepolarization as the second polarization 785. In system 1000, thetransmit polarization 795 can be the same as the polarizations 780, 785such that the transmit antenna 810 can have the same polarization as thereceive antennas 825, 835.

These receive antennas 825, 835 can be positioned on either side of thetransmit antenna 810. For example, the receive antennas 825, 835 and thetransmit antenna 810 can be positioned along the direction of the focalplane drift, discussed above. The physical proximity of the receiveantennas 825, 835 to the transmit antenna 810 is selected to compensatefor the focal plane drift for the specific target distance, e.g., therange of the object 702 to the scanner 740.

FIG. 11 is a block diagram of an example of a LIDAR sensor system 1100including the optical components of FIG. 10 . The LIDAR sensor system1100 can incorporate features of the LIDAR sensor system 500 and opticmodule 524 described with reference to FIGS. 5 and 6 , respectively. TheLIDAR sensor system 1100 can facilitate pitch-catch compensation, i.e.accounting for time delays or other offsets resulting from theround-trip path of the transmit beam outputted from the LIDAR sensorsystem 1100, reflected or otherwise scattered by object(s), and thenreturned as the return beam to the LIDAR sensor system 1100 fordetection and processing, which might otherwise affect characteristicsof the LIDAR sensor system 1100 such as signal-to-noise ratio.

Because the system 1000 is similar to the system 800, except for thepolarizations of the receive antennas 825, 835 being aligned with thepolarization of the transmit antenna 810, the block diagram depicted inFIG. 11 is similar to the block diagram depicted in FIG. 9 . However,since the polarizations of the receive antennas 825, 835 are notopposite of the polarization to the transmit antenna 810, the displacer905 (as well as wave plate 915 and or a Faraday rotator) can be omitted.For example, in the LIDAR sensor system 900, the displacer 905 candisplace the return beam 755 in the opposite polarization to thetransmit beam 735 by a fixed amount. However, in the LIDAR sensor system1100, the displacement of the return beam 755 it is not needed when thepolarizations 780, 785, 795 are the same.

FIG. 12 is a block diagram of an example of optical components of asystem 1200. The system 1200 can include components of and/or be used toimplement various LIDAR sensor systems described herein, such as thetransmitter 710 and the receiver 712. For example, the system 1200 canbe used to implement a receiver of a single polarization, and a switchedlocal oscillator.

The system 1200 is similar to the system 800. However, the mixers 840,845 are in communication with two independent and balancedphotodetectors, instead of the single photodetector, e.g., the receiver712, with two photodiodes, e.g., the grating couplers 725, 730. As such,the system 1200 can include a receiver 1205, e.g., a second receiver.The receiver 1205 can include the grating coupler 730. The receiver 712can include the grating coupler 725. The mixer 840 can provide thesignal 850 to the receiver 712, similar to the system 800. However, inthe system 1200, the mixer 845 can provide the signal 855 to thereceiver 1205.

In the system 1200, the local oscillator 815 can be passively splitbetween the mixer 840 and the mixer 845. For example, the localoscillator 815 can actively switch the LO signal between the mixer 840and the mixer 845 based on the scanning direction of the scanner 740.For example, the local oscillator 815 can transmit the reference beam820, e.g., the first LO signal, to the mixer 840. For example, the localoscillator 815 can transmit the reference beam 830, e.g., the second LOsignal, to the mixer 845.

FIG. 13 is a block diagram of an example of optical components of asystem 1300. The system 1300 can include components of and/or be used toimplement various LIDAR sensor systems described herein, such as thetransmitter 710 and the receiver 712. For example, the system 1300 canbe used to implement a receiver of a single polarization, and a switchedlocal oscillator.

The system 1300 is similar to the system 1000 such that the displacer905 (as well as the wave plate 915 and/or a Faraday rotator) can beomitted during operation. However, similar to the system 1200, themixers 840, 845 are in communication with two independent and balancedphotodetectors, instead of the single photodetector, e.g., the receiver712, with two photodiodes, e.g., the grating couplers 725, 730. As such,the system 1300 can include the receiver 1205. The receiver 1205 caninclude the grating coupler 730. The receiver 712 can include thegrating coupler 725. The mixer 840 can provide the signal 850 to thereceiver 712, similar to the system 800. However, in the system 1300,the mixer 845 can provide the signal 855 to the receiver 1205. Further,similarly to the system 1200, the local oscillator 815 can be passivelysplit between the mixer 840 and the mixer 845.

FIG. 14 is a block diagram of an example of optical components of asystem 1400. The system 1400 can include components of and/or be used toimplement various LIDAR sensor systems described herein, such as thetransmitter 710 and the receiver 712. For example, the system 1400 canbe used to implement a receiver of a single polarization, and a switchedlocal oscillator.

The system 1400 is a combination of the system 800 and the system 1000.As such, the system 1400 can include two separate local oscillators. Forexample, the system 1400 can include the local oscillator 815 and alocal oscillator 1405, e.g., a second local oscillator. The localoscillator 1405 can function similar to or the same as the localoscillator 815. For example, the local oscillator 1405 can output LOsignals. For example, the local oscillator 1405 can actively switch theLO signal between at least to mixers based on the scanning direction ofthe scanner 740. For example, the local oscillator 1405 can output athird LO signal and a fourth LO signal. The LO signals can be similar toor the same as reference beam 512. For example, the local oscillator1405 can transmit the third LO signal, e.g., a reference beam 1410. Forexample, the local oscillator 1405 can transmit the fourth LO signal,e.g., a reference beam 1420. By the local oscillator 1405 switching theLO signal, the amount of power required by the local oscillator 1405 canbe reduced.

The system 1400 can include a receive antenna 1415 and a receive antenna1425. The receive antennas 1415, 1425 are similar to the receiveantennas 825, 835. For example, the receive antennas 1415, 1425 canreceive the return beam 755, as discussed more below.

The system 1400 can include a mixer 1430 and a mixer 1435. The mixers1430, 1435 can be similar to or the same as the mixers 840, 845. Themixers 1430, 1435 can receive signals, as discussed more below. Themixer 1430 can output a signal 1440, as discussed more below. The mixer1435 can output a signal 1445, as discussed more below.

FIG. 15 is a block diagram of an example of a LIDAR sensor system 1500including the optical components of FIG. 14 . The LIDAR sensor system1500 can incorporate features of the LIDAR sensor system 500 and opticmodule 524 described with reference to FIGS. 5 and 6 , respectively. TheLIDAR sensor system 1500 can facilitate pitch-catch compensation, i.e.accounting for time delays or other offsets resulting from theround-trip path of the transmit beam outputted from the LIDAR sensorsystem 1500, reflected or otherwise scattered by object(s), and thenreturned as the return beam to the LIDAR sensor system 1500 fordetection and processing, which might otherwise affect characteristicsof the LIDAR sensor system 1500 such as signal-to-noise ratio.

The LIDAR sensor system 1500 can include the displacer 905 and thecollimator 604, similar to the system 800 depicted in FIG. 8 . However,in the system 1400, the LIDAR sensor system 1500 can include the waveplate 915. The wave plate 915 can be a quarter wave plate. For example,the wave plate 915 can convert the transmit beam 735 from linear tocircular polarization (e.g., left or right circular) as the transmitbeam 735 is outputted from the transmitter 710. The wave plate 915 canconvert the return beam 755 (e.g., the return beam 755 having beenreflected by a polarization maintaining target) to an opposite circularpolarization orthogonal to that of the transmit beam 735 (e.g., left toright or vice versa) to be displaced by the displacer 905.

The LIDAR sensor system 1500 can include a grating coupler 1510 and agrating coupler 1520. The grating couplers 1510, 1520 can receive thereturn beam 755 provided by the scanner 740. For example, the gratingcoupler 1510 can receive a third component 1505 of the return beam 755provided by the scanner 740. For example, the grating coupler 1520 canreceive a fourth component 1525 of the return beam 755 provided by thescanner 740. The third component 1505 of the return beam 755 can be at athird polarization 1515. The fourth component 1525 of the return beam755 can be at a fourth polarization 1530.

As discussed above, the LIDAR sensor system 1500 can include the receiveantenna 1415 and the receive antenna 1425 of the receiver 1205. Thereceive antenna 1415 can be implemented by the grating coupler 1510 ofthe receiver 712. For example, the receive antenna 1415 can be anoptical antenna integrated onto the chip 705. The receive antenna 1415can couple the third component 1505 of the return beam 755 onto the chip705 from free space. The receive antenna 1415 can be oriented at anangle relative to a surface on which the receive antenna 1415 isprovided corresponding to the third polarization 1515 of the thirdcomponent 1505 of the return beam 755. The receive antenna 1425 can beimplemented by the grating coupler 1520 of the receiver 712. Forexample, the receive antenna 1425 can be an optical antenna integratedonto the chip 705. The receive antenna 1425 can couple the fourthcomponent 1525 of the return beam 755 onto the chip 705 from free space.The receive antenna 1425 can be oriented at an angle relative to asurface on which the receive antenna 1425 is provided corresponding tothe fourth polarization 1530 of the fourth component 1525 of the returnbeam 755.

The receive antenna 1415 can receive the return beam 755. For example,the receive antenna 1415 can receive the third component 1505 of thereturn beam 755. As such, the receive antenna 1415 can be oriented atthe same polarization as the third component 1505 of the return beam755. For example, the receive antenna 1415 can have the samepolarization as the third polarization 1515. The receive antenna 1415can provide the third component 1505 of the return beam 755 to the mixer1430.

The receive antenna 1425 can receive the return beam 755. For example,the receive antenna 1425 can receive the fourth component 1525 of thereturn beam 755. As such, the receive antenna 1425 can be oriented atthe same polarization as the fourth component 1525 of the return beam755. For example, the receive antenna 1425 can have the samepolarization as the fourth polarization 1530. The receive antenna 1425can provide the fourth component 1525 of the return beam 755 to themixer 1435.

As discussed above, the mixers 1430, 1435 can receive signals. Forexample, the mixer 1430 can receive the reference beam 1410, e.g., thethird LO signal. For example, the mixer 1430 can receive the thirdcomponent 1505 of the return beam 755 from the receive antenna 1415. Forexample, the mixer 1435 can receive the reference beam 1420, e.g., thefourth LO signal. For example, the mixer 1435 can receive the fourthcomponent 1525 of the return beam 755 from the receive antenna 1425.

As discussed above, the mixers 1430, 1435 can output signals. Forexample, the output signals can be based on the signals that each of themixers 1430, 1435 received from the receive antennas 1415, 1425,respectively. For example, the output signals can be based on thesignals that each of the mixers 1430, 1435 received from the localoscillator 1405. For example, the mixers 1430, 1435 can output signalsresponsive to the return beam 755 and the reference beams 1410, 1420.For example, the mixers 1430, 1435 can mix the return beam 755 and thereference beams 1410, 1420 and each output a signal.

The mixer 1430 can output the signal 1440. The signal 1440 can beresponsive to and based on the third component 1505 of the return beam755 and the reference beam 1410. The mixer 1435 can output the signal1445. The signal 1445 can be responsive to and based on the fourthcomponent 1525 of the return beam 755 and the reference beam 1420. Themixers 1430, 1435 can provide the signals 1440, 1445 to two photodiodes,e.g., the grating couplers 1510, 1520, respectively. The two photodiodescan have two physically separate optical inputs such that the mixers1430, 1435 can provide the signals 1440, 1445 to a single photodetector.For example, the mixers 1430, 1435 can provide the signals 1440, 1445 tothe receiver 1205.

FIG. 16 is a block diagram of an example of optical components of asystem 1600. The system 1600 can include components of and/or be used toimplement various LIDAR sensor systems described herein, such as thetransmitter 710 and the receiver 712. For example, the system 1600 canbe used to implement a receiver of a single polarization, and a switchedlocal oscillator.

The system 1600 is similar to the system 1400. However, similarly to thesystem 1200, the mixers 1430, 1435 are in communication with twoindependent and balanced photodetectors, instead of the singlephotodetector, e.g., the receiver 1205. As such, the system 1600 caninclude a receiver 1605, e.g., a third receiver, and a receiver 1610e.g., a fourth receiver. The receiver 1605 can include the gratingcoupler 1510. The receiver 1610 can include the grating coupler 1520.Additionally, the receiver 712 can include the grating coupler 725 andthe receiver 1205 can include the grating coupler 730. The mixer 840 canprovide the signal 850 to the receiver 712. The mixer 845 can providethe signal 855 to the receiver 1205. The mixer 1430 can provide thesignal 1440 to the receiver 1605. The mixer 1435 can provide the signal1445 to the receiver 1610.

Having now described some illustrative implementations, it is apparentthat the foregoing is illustrative and not limiting, having beenpresented by way of example. In particular, although many of theexamples presented herein involve specific combinations of method actsor system elements, those acts and those elements can be combined inother ways to accomplish the same objectives. Acts, elements andfeatures discussed in connection with one implementation are notintended to be excluded from a similar role in other implementations orimplementations.

The phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including” “comprising” “having” “containing” “involving”“characterized by” “characterized in that” and variations thereofherein, is meant to encompass the items listed thereafter, equivalentsthereof, and additional items, as well as alternate implementationsconsisting of the items listed thereafter exclusively. In oneimplementation, the systems and methods described herein consist of one,each combination of more than one, or all of the described elements,acts, or components.

Any references to implementations or elements or acts of the systems andmethods herein referred to in the singular can also embraceimplementations including a plurality of these elements, and anyreferences in plural to any implementation or element or act herein canalso embrace implementations including only a single element. Referencesin the singular or plural form are not intended to limit the presentlydisclosed systems or methods, their components, acts, or elements tosingle or plural configurations. References to any act or element beingbased on any information, act or element can include implementationswhere the act or element is based at least in part on any information,act, or element.

Any implementation disclosed herein can be combined with any otherimplementation or embodiment, and references to “an implementation,”“some implementations,” “one implementation” or the like are notnecessarily mutually exclusive and are intended to indicate that aparticular feature, structure, or characteristic described in connectionwith the implementation can be included in at least one implementationor embodiment. Such terms as used herein are not necessarily allreferring to the same implementation. Any implementation can be combinedwith any other implementation, inclusively or exclusively, in any mannerconsistent with the aspects and implementations disclosed herein.

Where technical features in the drawings, detailed description or anyclaim are followed by reference signs, the reference signs have beenincluded to increase the intelligibility of the drawings, detaileddescription, and claims. Accordingly, neither the reference signs northeir absence have any limiting effect on the scope of any claimelements.

Systems and methods described herein may be embodied in other specificforms without departing from the characteristics thereof. Furtherrelative parallel, perpendicular, vertical or other positioning ororientation descriptions include variations within +/−10% or +/−10degrees of pure vertical, parallel or perpendicular positioning.References to “approximately,” “about” “substantially” or other terms ofdegree include variations of +/−10% from the given measurement, unit, orrange unless explicitly indicated otherwise. Coupled elements can beelectrically, mechanically, or physically coupled with one anotherdirectly or with intervening elements. Scope of the systems and methodsdescribed herein is thus indicated by the appended claims, rather thanthe foregoing description, and changes that come within the meaning andrange of equivalency of the claims are embraced therein.

The term “coupled” and variations thereof includes the joining of twomembers directly or indirectly to one another. Such joining may bestationary (e.g., permanent or fixed) or moveable (e.g., removable orreleasable). Such joining may be achieved with the two members coupleddirectly with or to each other, with the two members coupled with eachother using a separate intervening member and any additionalintermediate members coupled with one another, or with the two memberscoupled with each other using an intervening member that is integrallyformed as a single unitary body with one of the two members. If“coupled” or variations thereof are modified by an additional term(e.g., directly coupled), the generic definition of “coupled” providedabove is modified by the plain language meaning of the additional term(e.g., “directly coupled” means the joining of two members without anyseparate intervening member), resulting in a narrower definition thanthe generic definition of “coupled” provided above. Such coupling may bemechanical, electrical, or fluidic.

References to “or” can be construed as inclusive so that any termsdescribed using “or” can indicate any of a single, more than one, andall of the described terms. A reference to “at least one of ‘A’ and ‘B’”can include only ‘A’, only ‘B’, as well as both ‘A’ and ‘B’. Suchreferences used in conjunction with “comprising” or other openterminology can include additional items.

Modifications of described elements and acts such as variations insizes, dimensions, structures, shapes and proportions of the variouselements, values of parameters, mounting arrangements, use of materials,colors, orientations can occur without materially departing from theteachings and advantages of the subject matter disclosed herein. Forexample, elements shown as integrally formed can be constructed ofmultiple parts or elements, the position of elements can be reversed orotherwise varied, and the nature or number of discrete elements orpositions can be altered or varied. Other substitutions, modifications,changes and omissions can also be made in the design, operatingconditions and arrangement of the disclosed elements and operationswithout departing from the scope of the present disclosure.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below”) are merely used to describe the orientation of variouselements in the FIGURES. It should be noted that the orientation ofvarious elements may differ according to other exemplary embodiments,and that such variations are intended to be encompassed by the presentdisclosure.

What is claimed is:
 1. A light detection and ranging (LIDAR) sensorsystem for a vehicle, comprising: a transmitter comprising a firstgrating coupler, the transmitter configured to output a transmit beam; areceiver comprising a plurality of second grating couplers, theplurality of second grating couplers spaced from the first gratingcoupler; a scanner configured to receive the transmit beam from thetransmitter, direct the transmit beam toward an environment of thevehicle, receive a return beam from reflection of the transmit beam byan object in the environment, and direct the return beam to thereceiver; a collimator between the transmitter and the scanner, thecollimator configured to collimate the transmit beam; a circulatorbetween the collimator and the plurality of second grating couplers,each second grating coupler of the plurality of second grating couplersconfigured to receive a respective component of the return beam fromfree space from the circulator; a first mixer and a second mixerrespectively coupled with one of the second grating couplers; and alocal oscillator configured to switch a reference signal between thefirst mixer and the second mixer.
 2. The LIDAR sensor system of claim 1,wherein the first grating coupler comprises a chip having at least oneof an etching or a material deposited on the chip.
 3. The LIDAR sensorsystem of claim 1, wherein the scanner is configured to scanbi-directionally.
 4. The LIDAR sensor system of claim 1, wherein: theplurality of second grating couplers comprises a first receive gratingcoupler that is configured to receive the respective component of thereturn beam as a first component of the return beam associated with afirst polarization; and the plurality of second grading couplers alsocomprises a second receive grating coupler that is configured to receivethe respective component of the return beam as a second component of thereturn beam having a second polarization, the first polarization beingdifferent than the second polarization.
 5. The LIDAR sensor system ofclaim 1, wherein: the first grating coupler and the plurality of secondgrating couplers are in a same plane; the first grating coupler isconfigured to output the transmit beam at a first polarization; and theplurality of second grating couplers are configured to receive thereturn beam at the first polarization or at a second polarizationdifferent than the first polarization.
 6. The LIDAR sensor system ofclaim 1, wherein the first grating coupler is oriented at an anglerelative to a surface on which the first grating coupler is provided,the angle corresponding to a polarization of the transmit beam.
 7. TheLIDAR sensor system of claim 1, wherein: the plurality of second gratingcouplers comprises a first receive grating coupler that is spaced fromthe first grating coupler by a spacing associated with a target rangefrom the scanner for detecting the object.
 8. The LIDAR sensor system ofclaim 7, wherein: the spacing is a first spacing, the target range is afirst target range, and the plurality of second grating couplerscomprises a second receive grating coupler that is spaced from the firstgrating coupler by a second spacing associated with a second targetrange that is further from the scanner than the first target range. 9.The LIDAR sensor system of claim 1, wherein the plurality of secondgrating couplers comprises a second receive grating coupler that isspaced by about 8 micrometers to about 24 micrometers from the firstgrating coupler.
 10. The LIDAR sensor system of claim 1, wherein thefirst grating coupler and the plurality of second grating couplers arearranged in an array on a chip.
 11. The LIDAR sensor system of claim 1,wherein the transmitter and the receiver are on a chip made from asilicon material or a III-V semiconductor material.
 12. An autonomousvehicle control system, comprising: a LIDAR sensor system, comprising: afirst grating coupler configured to output a transmit beam; a secondgrating coupler spaced apart from the first grating coupler; a thirdgrating coupler spaced apart from the first grating coupler; a scannerconfigured to receive the transmit beam from the transmitter, direct thetransmit beam to an environment, receive a return beam from reflectionof the transmit beam by an object located in the environment, and directthe return beam to the second grating coupler; a collimator between thefirst grating coupler and the scanner, the collimator configured tocollimate the transmit beam; a circulator between (i) the collimator and(ii) the second grating coupler and the third grating coupler, thesecond grating coupler and the third grating coupler configured toreceive a respective component of the return beam from free space fromthe circulator; a first mixer and a second mixer respectively coupledwith one of the second grating coupler or the third grating coupler; anda local oscillator configured to switch a reference signal between thefirst mixer and the second mixer; and one or more processors configuredto: determine at least one of a range to the object or a velocity of theobject based on the return beam; and control operation of an autonomousvehicle responsive to the at least one of the range or the velocity. 13.The autonomous vehicle control system of claim 12, wherein the one ormore processors are configured to determine the range to the objectbased on a time of flight associated with the return beam.
 14. Theautonomous vehicle control system of claim 12, further comprising amodulator configured to perform at least one of frequency modulation orphase modulation of a beam that the first grating coupler outputs as thetransmit beam.
 15. The autonomous vehicle control system of claim 12,wherein: the second grating coupler is configured to receive therespective component of the return beam as a first component of thereturn beam having a first polarization; and the third grating coupleris configured to receive the respective component of the return beam asa second component of the return beam having a second polarization, thefirst polarization being different than the second polarization.
 16. Theautonomous vehicle control system of claim 12, wherein: the firstgrating coupler and the second grating coupler are spaced apart by afirst spacing associated with a first target range from the LIDAR sensorsystem for detecting the object, and the first grating coupler and thethird grating coupler are spaced apart by a second spacing associatedwith a second target range from the LIDAR sensor system that is greaterthan the first target range.
 17. An autonomous vehicle, comprising: atransmitter comprising a first grating coupler, the transmitterconfigured to output a transmit beam; a receiver comprising a secondgrating coupler spaced apart from the first grating coupler and a thirdgrating coupler spaced apart from the first grating coupler; a scannerconfigured to receive the transmit beam from the transmitter, direct thetransmit beam to an environment, receive a return beam from reflectionof the transmit beam by an object located in the environment, and directthe return beam to the receiver; a collimator between the transmitterand the scanner, the collimator configured to collimate the transmitbeam; a circulator between the collimator and the plurality of secondgrating couplers, each second grating coupler of the plurality of secondgrating couplers configured to receive a respective component of thereturn beam from free space from the circulator; a first mixer and asecond mixer respectively coupled with one of the second grating coupleror the third grating coupler; and a local oscillator configured toswitch a reference signal between the first mixer and the second mixer;a steering system; a braking system; and a vehicle controller comprisingone or more processors configured to: determine at least one of a rangeto the object or a velocity of the object using the return beam and thereference signal; and control operation of at least one of the steeringsystem and the braking system responsive to the at least one of therange or the velocity.
 18. The autonomous vehicle of claim 17, wherein:the second grating coupler is configured to receive a first component ofthe return beam associated with a first polarization; and the thirdgrating coupler is configured to receive a second component of thereturn beam associated with a second polarization different than thefirst polarization.
 19. The autonomous vehicle of claim 17, wherein thefirst grating coupler and a second grating coupler are spaced apart fromeach other based on a target range from the scanner for detecting theobject.
 20. The LIDAR sensor system of claim 1, wherein the firstgrating coupler and the second grating coupler are provided on a sameintegrated chip, the integrated chip comprising a semiconductormaterial.